镧对非晶/纳米晶Ni-Mo合金镀层结构及性能的影响

Effects of Lanthanum on Microstructure and Properties of Amorphous/Nanocrystalline Ni-Mo Alloy Coating

在碱性条件下获得了非晶/纳米晶Ni-Mo,Ni-Mo-La合金复合镀层,利用X射线衍射(XRD)、扫描电镜(SEM)和电化学分析研究了镧(La)对获得镀层组织、表面形貌及化学活性的影响。结果表明,随着镧含量的增加,镀层中钼含量升高,形成的Ni-Mo合金的二次相出现α-NiMo,β-Ni4Mo,γ-Ni3Mo和δ-Ni8Mo,同时镀层表面团聚颗粒逐渐分散、细小且致密,镀层表面变得平整光滑。镀层的显微硬度随着La含量的增加先升高后降低。电化学性能实验表明,Ni-Mo-La合金具有良好的电催化性能与合金镀层中的稀土化合物有较高的化学活性有关,其在电解过程中为合金的催化作用提供了活性中心,降低了析氢过电位。

The amorphous/nanocrystalline Ni-Mo and Ni-Mo-La alloy co-depositions were obtained in alkaline solution. The effects of La on the composition microstructure, morphology and chemical activation of the deposition were investigated by X-ray diffraction （XRD） , scanning electronic morphology （ SEM ） and electrochemical workstation. It was found that the Mo content in the deposition increased with the increasing La correspondingly. The α-NiMo, β-Ni4Mo, γ-Ni3Mo and δ-NisMo compounds were formed in the Ni-Mo alloy. And the particles of coating surface became smal-ler and dispersed more uniformly, which resulted in a smooth and compact coating surface. The microhardness of the coating firstly increased and then decreased with increasing La content in the deposition. The Ni- Mo-La alloy exhibited a good catalytic property. This could be related to the high chemical activity of the La-contained compounds, which provided catalyst active center for the electrolysis process and consequently decreased the potential voltage of the hydrogen evolution.